We are estimating risks of breast and ovarian cancer in the general population and in high-risk women with genetic alterations in BRCA1 and BRCA2 using diverse data sources. We surveyed the Jewish community of Washington, DC in 1997; we collaborated with investigators in Israel in a case-control study of ovarian cancer; we collaborate with NCI and other investigators in the Prostate, Lung, Colon and Ovarian Cancer Screening trial. We are developing models of the cancer risks in mutation carriers and in other women, according to their reproductive histories and exposure to hormones.